A HVAC system typically includes a compressor, a condenser, an evaporator and an expansion device forming a refrigeration circuit. Flooded and falling-film evaporators generally are known and often have a construction of a tube bundle within a shell. Such evaporators are typically used in HVAC chillers to cool a process fluid (e.g., water) flowing in the tube bundle which, in turn, is typically used in connection with a heat exchanger coil or air-handling unit to cool air moving through the coil or air-handling unit. The tube bundle is often stacked up from a bottom of the evaporator. In a flooded evaporator, ideally, the tube bundle is covered with refrigerant in the shell to help maximize heat exchange between the refrigerant and the processed fluid. A fluid level of the refrigerant in the evaporators may be controlled by an expansion device.
The compressor of the HVAC system often requires lubricating oil to lubricate moving parts of the compressor. In the HVAC system, the oil may circulate in the refrigeration circuit along with the refrigerant, and then return to the compressor. The HVAC system often incorporates methods and systems for managing the fluids, such as refrigerant and/or oil.